package PAT.乙.模拟;

import java.util.Scanner;

/**
 * 程序运行时间
 *
 * @author yang
 * @date 2021/12/15
 */
public class 程序运行时间 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int ans = (b - a) ;
        if ((ans % 100) >= 50) ans = ans / 100 + 1;
        else ans /= 100;
        System.out.printf("%02d:%02d:%02d",ans/3600,ans % 3600/60,ans % 60);
    }
}
